Liquid storage system



May 2, 1933. w. J. PETER 1,907,001

LIQUID STORAGE SYSTEM Filed March 16, 1931 uNvENToR WILL/AM d. PETER Patented May 2, 1933 UNITED STATES PATENT OFFICE WILLIAM J'. PETER, OF NEW YORK, N. Y., .ASSIGNOR TO AQUA SYSTEMS INCORPORATED,

0F YORK, N. Y., A CORLPORATION OF NEW YORK LIQUID STORAGE SYSTEM Y 'Application iled March 16, 1931. Serial No. 523,013.

This inventief-relates to a liquid storage..

prevent inhalationfof a charge of fresh air;

and such'object is better. attained when the stored liquid preferably .lls the ltank to its top, but without unduev pressure or force thereaga-inst, to primarilyex'clude the air and i thus the tank does notlhave anfair space between the liquid .surface and at least thegreater part of the top of the tank and consequently this portion of theftank cannot breathe.A Thus is `avoided vaporization and formation of. explosive mixtures when storing oil and gasoline, particularly in tanks abovethe ground. `Economy and safety is promoted. This primary object is carried out by compensatingfor variation in volume of stored liquid A'by admitting or withdravv ing fromthe tank an amount. of displacement liquidequal to the change in volume ofthe stored liquid.

So called tank; breathing results in gasoline and other va or. losses .forming from volatile Stored liquids'andcis due to the rise and fall or variation in heightof the Vupper surface Vofthe stored liquid and occurs by operation of two principal causes. This breathing is brought about inA one; instance largely by night and day or even seasonal temperature variations which expands the liquid injtheltank and thus reducesthe air space at the top whichexpels or displaces and hence wastes some of thevgzni vapors of the stored liquid, and upon cooling of the liquid the contraction thereof conversely increases the volume ofthe air space at the top of the tank and fresh4 airis then drawn into l the tank to subsequently be expelled and .carf

ry ofi'l vapor. The repetition of this breathing, due to variation in volume of the liquids, by night and day causes a substantial gasoline loss Where the tank is large. Storage vtank breathing is also caused in another instance by drawing off the stored liquid for` use and then by relling the storage tank to replenish the stored supply; and these operations, or transference of liquid, causes inhaling and eXhaling of the storage tank.

After a period of time in Which many exhalations and inhalations have taken place due to either cause,.temperature variations or liquid transference, the loss of stored liquid is considerable and therefore a reduction or elimination of breathing will bring about a sizable saving in loss of stored liquid.

The main object. or purpose above stated is effected by providing novel control means for overhead or above the ground tanks, by which the upper surface of the stored liquid remains at substantially aI predetermined level or height, preferably up against the top ofthe tank, irrespective of the expansion or Y.

contraction of the one or more immiscible liquids in the tank due to temperature changes occurring principally by reason of Warm days and cool nights or Weather conditions.

The main object or purpose above. stated is also effected by providing novel control means which maintains theupper surface of the stored oil, gasoline or .other liquid at substantially a predetermined level or height,

more especially against or in contact with the course of business or use of the storage system.

It is also an object to provide novel means,

when a hydraulic pumping system is used,

to prevent the upper surface of a displace- .ment liquid, such as Water under the stored liquid as oil, from exceeding a predetermined high level or receding below a predetermined low'level. If water were permitted to rise above the stored oil outlet pipe located at the top of the tank, it would then be possible to draw oil water with the oil, but a control device is employed to prevent the water from reaching the oil delivery pipe leading from the tank. Similarly, it would be possible to drain ofi oil through the water drain outlet located at the bottom of the tank which usually goes to a Waste drain or to the sewer, but to avoid this loss of oil the invention provides means to prevent the lower oil level or surface, which ,is in contact with the water, from receding to and reaching the water drain.

Another object of the invention is to provide a liquid storage system having anovel float and electrically operated valve means to maintain the upper surface of the oil at substantially a constant predetermined level, or against the top of the tank, and to prevent the upper surface of the Wat-er from exceeding a predetermined high or, receding below a predetermined low level. In this way a minimum volume of water is retained in the bottoml of the tank when said tank is completely filled with oil, and conversely7 a minimum volume of oil remains in the upper portion of the tank when said tank is filled With water. Thus the adjacent or contacting surfaces of the two immiscible liquids, as shown in the drawing, have limiting levels Within the tank, i. e., an upper level and lower level beyond which they do not go. The reference characters HW and LW on the drawing in two positions indicate the two limiting levels of the adjacent surface of the immiscible liquids.

Other objects of the invention will be more appa-rent from the following description, taken in connection withv the accompanying drawing, which illustrates the principles involved and in which:

Figure 1 shows a diagram of the invention and is a section through a storage tank filled with oil to the top and resting on the hydraulic pumping liquid such as Water and showing the float controlled electrically operated valve means by whichthe upper and lower predetermined limiting levelsor ad.- jacent contacting surfaces, of stored liquid and displacement liquid arev controlled; and the position of operating parts is such that a valve control means is open in the discharge pipe line for the displacement liquid to flow out because the upper oil surface is abnormally high and hence the automatic control is functioning to lower and adjust the upper oil level. y

Figure 2 shows a suit-able and well known type of motor-driven opened and closed valve which may be substituted for the solenoid type of` operated valve shown in Figure 1.

any dispacement liquid.

fThe storage reservoir 10 is shown to store The motors or solenoids are controlled from the float and switclimeans on the tank.

` Liquid storage systems for storing liquids, such as oils and other liquids which are more or less volatile, have a. considerable loss through evaporation when stored in vtanks above the ground, and this results from temperature changes throughout the day as well as throughout the seasons when such liquids are stored for any long period of time. Such loss by evaporation occurs even though the'storage tank or reservoir is covered since a vent must be provided at the top of the tank and under the varying daily temperatures as well as under the varying tem eratures over a longer period, the liqui expands considerably whichraises the level of the liquid in the storage tank and this, in turn, reduces the volume of the air space above the liquid. Reduction of the air space above the liquid in the tank forces the evap orated liquid or gas in the air space out of the vent upon the tank. Upon cooling at night time, the liquid contracts which, in turn, increases the volume of space above the liquid in the tank and air is drawn through the'vent into the tank. This breathing in and out action is a result of alternate expansion and contraction of the liquid and the evaporated liquids existing as a gas i1-. the lspace at the top of the tank are continually being lost through the vent i-n a continous breathing process.

The storage system herein pertains particularly to the storing of light oils, gasoline and other liquids in a reservoir which are hydraulically removed from the reservoir by feeding a displacement liquid, such as water, into the tank so that the lighter and immiscible oils or gasoline float on the displacement liquid. The stored liquid may be and preferably is removed from the tank by draining it off by gravity through a pipe carried to' the top of the tank, and. it is important, therefore, that the displacement liquid shall not rise to the stored-liquid outlet else the water would follow the oil out through the oil delivery ,pipe when the oil supply is exhausted in the tank. It is also equally importantl that the water be prevented from receding below a predetermined level in the tank so that the oil will not pass out of the tank through the water outlet pipe through which the water fiows when the tank is being filled with oil.

By way of explanation and brevity, the terni oil used in the description and claims means any stored liquid and water means gasoline, oil or other liquids O. which are immiscible with a displacement liquid and float thereupon. Water is the preferred displacement liquid, inasmuch as it is the cheapestand most readily obtained, as Well as having a high specific gravity so that oils and gasoline float thereupon. The tank 10 has a stored-liquid outlet pipe 11 connected at the top and in which a valve 12 isprovided for controlling the delivery of the oil therefrom. A stored-liquid inlet pipe 13 is also connected at the, top of .the tank and preferably" feeds into the tank at a point a little below the outlet pipe 11. The oil inlet pipe 13 has a control valve 14.

A displacement-liquid or water inlet connection or pipe 17 connects with'the bottom of the tank and has an electrically operated valve 18 therein. The tank also has a displacement-liquid or Water outlet connection 2O in which is provided an electrically operated valve 21. The water inlet pipe 17 or tank 10 has an inlet or-by-pass 22 with a manually, operated valveV 23 which permits of thevinflowof water'to the tank independently of the inlet pipe and valve control means 17, 18. An outlet connection or pipe 24 has a valve 25 for discharging water from the tank 10. The two water pipes 22 and 24 provide an independent Water supply and drain to and from the tank for manual control of water transfer operations, ywhile the pipes 17 and 20 are automatic in water transfer operations.

The reservoir or tank 10 has a float box 30 at its top which is considerably smaller than the tank 10 and consequently, the space at the top of the tank is considerably reduced in volume by maintaining the top level of the stored liquid within the float box. In addition, any expansion or contraction of the stored and displacement liquids in the tank as a result of temperature changes amplilies the expansion and contraction by increasing the extent of rise or fall of the level of the? stored liquid O and consequently the liquid" level control means therein is rendered more sensitive to the expansion and contractionof the liquids in the tank.' The reduced volume of space above the liquid in the float box 30 also reduces the volume of gases exhaled out of the-tank or in other words, reduces the c2;-

tentofthe breathing. A vent 31 connects the top of the float box 30 with the outer atmosphere.

A float 33 which floats upon the stored liquid Oy is carried within the float box 30 on a pivot 34 supported in the sides of the lloat box 30. An arm 35 is carried on the pivot 34 which arm is electrically conducting over .a

portion of its length but is insulated from the pivot 34, tank 10 and other mechanismby the insulator 36. A pair of contacts 37 are posi` tioned adjacent to the arm 35'so that when the float 33 falls as a result ofthe lowering of the level of the liquid within the tank 10. an electrical circuit 39 is closed between the contacts 37 through the arm 35 by the-arm' engaging with the contacts-37. Similarlv, when the float rises or lifts asa result of the box 50 and is controlled by the level of the displacement liquid in the tank 10 when it reaches the float box. The float 51 is carried upon a pivot 52 carried by the sides of the float box 50. An electrically conducting arm 53 is carried on the pivot 52 which 'is'insulated from the pivot 52 and tank 10 by the insulator 54. A pair of contacts 55 are positioned adjacent to the arm 53 so that the electrical circuit4 39 is closed between the contacts and through the arm 53 when the lloat 51 is in its lower position which position the ioat assumes when the level of the displacement liquid l/V in the tank is below the float even `though the float is immersed in the stored liquid O since the float is so adjusted that it .will not float but sinks in the stored, liquid O. The contacts 55 are .connected in series with the contacts 37 in the electrical circuit 39 so that the float 51 through the contacts 55 also controls, under certain conditions to 'be discussed hereinafter, the solenoid 42 and the electrically operated valve 18 in the inlet connection 17 for the displacement liquid W. The valve 18 may then be termed a displacernent-liquidinlet valve.

. A third loat box 58 is connected with the bottomof the tank 10 and a float 59 which sinks in the stored liquid O and floats upon the displacement liquid W, is carried therein upon the pivot 60 passing through and supported by the side wall of the float box. An electrically conducting varm 61 is carried uponthe pivot 60 but is insulated therefrom by the insulator 62 as in the other arms 35 and 53. A pair of contacts 63 are positioned adjacent to the arm 61 so that the arm con tacts therewith when the float 59 is in its upper position. rllhe float 59 assumes its upper position when it is` immersed in the displacement liquid W and falls or sinks and breaks its engagement with the contacts 63 when immersed in stored liquid O to break the elcctrical connection between the arm 61 and the contacts 63. 'lhe float 59 is adjusted so that it sinks iny stored liquid 0 and iloats in the displacement liquid W and corresponds in this respect to the Heat 51. The contacts 63 let connection 20 for the displacement liquid W. The valve 21 is therefore a displacement-liquid outlet valve. The electricalcircuits 39 and 40 controlling the solenoids 42 and 45 are connected with a source of electrical potential 65 through the sw1tch66.

Although float boxes 50 and .58 are provided for the floats 51 and 59 respectively at thetop and bottom of the tank or reservoir 10, it. is clear that such float boxes are not essential parts of the construction but provide convenient receptacles and mountings for the floats. lt is essential, however, that the floats be mounted or connected with the tank 10 so that they are responsive to the level of the liquid in the tank to which it is responsive. The float 33 is then means which are responsive to the level of stored liquid O and the .floats 51 and 59 are means which are responsive to the level of the displacement liquid W. The arms 35, 53 and 61 controlled by the respective floats 33, 51 and 59 are switching means when taken in conjunction with their coacting contacts 37, 38 and 63 respectively. The switching means as previously described, control the valves 18 and 21 by which displacement liquid W is permitted to flow into or be discharged' from the tank 10.

The electrically controlled valves 18 and 21 are shown to be operated and controlled by solenoids 42 and 45 which are merely illustrative of any electrically operated valve which may be utilized to accomplish the same result. In Figure 2 there is shown a valve 70 which is operated by an electric motor mechanism 71 which is well known in the trade and purchasable upon the market and, consequently, its construction will not be described herein. Such a motor operated valve functions more satisfactorily than a solenoid valve inasmuch as the electrical circuit to the motor actua-ting the valve is broken and the electricity no longer flows when the valve reaches full open position or full closed position, whereas in the solenoid valves 42 and 45, the electric current continues to flow so long as the valves are held open. The continuous flow of the electricity as in the solenoid valves, uses electrical power and therefore is not as economical as the motor operated mechanism 71 and, in addition, the solenoids 42 and 45 tend to become heated when the valve remains open for any extended period which may result in some cases in an unsatisfactory condition. It is sufficient to state with respect to the motor operated valve 7 0 that upon the respective circuits being closed at the float switches or contacts, the valves are opened and upon thev circuits being opened, therespective valves are closed.

The motor operated valve 70, 71 of Figure 2 is also subject to control irrespective of the circuits 39 and 40. This valve by proper switch arrangement may be controlled at will and consequently function in a manner similar to the manual control of the displacement-liquid or water inlet and outlet connections through the by-pass connections 22 and 24 and their manually operable valves 23 and 25 irrespective of the position of the solenoid valves 18 and 21. It is clear that these bypass connections are the equivalent of manual opening or closing means for the solenoid valves themselves which form of valve more nearly coincides with the motor actuated valve 70, 71.

It is advantageous also to have the filling of the tank with oil to be automatically controlled so that in case the operator is negligent the oil will not rise above the high oil level HO when the water level has dropped below the level LW and the switch 61, 63 is opened. Opening of the switch 6 1, 63 opens the circuit 40 and closes the water outlet valve 21, and the valve cannot open even though the circuit is closed at the switch 35, 38 when the oil reaches the high oil level. It is clear therefore that under such condition it is possible to exceed the high oil level HO by continuing to pump or feed oil into the tank which oil would be wasted out of the vent 31 if the operator was not watching for the upward movement of the arm 35 to inform him that the high oil level had been reached and that the oil feed-in valve 14 should be closed.

The feeding in of oil into the tank 10 and the automatic control thereof is accomplished by running a circuit 75 from the switch 66 and including the float switch 35, 38 in series in the circuit. The circuit 75 connects with the electro-magnet 76 which controls the switch 77 in the motor circuit 7 8 to the motor 79 driving the pump 80. This circuit then begins from the switch 66 and through the float switch 35, 38 after which it branches through the circuit 75 to the electro-magnet 76 and directly back to the switch 66. Now then whenever the float 33 rises due to a high oil level and closes switch 35, 38'irrespective o f whether switch 61, 63 is open or closed the oil pump motor 79 is automatically stopped. It is clear that an automatic valve such as the valve 70, 71 or 18, 42 could be substituted for the pump 80 and motor 79 and such substitution is particularly suitable when the oil is fed into the tank 10 by gravity.

In operating the storage system, the storage tank 10 is first filled with water W and to accomplish this, the switch 66 connected the source of electrical potential 65 is close Theitank is completely empty at this stage and consequently the float 33 will be in its lowermost position which closes the circuit 39 through the contacts 37 and arm 35. The float 51 will also be in its lowermost position thereby closing the circuit 39 through the contacts 55 and arm 53 which are in series with the contacts 37 so that a completely closed circuit 39 exists through the solenoid 42 which is energized by the electrical'curlquently the valve 21 remains closed and the water continues to flow into the tank. The closing of the switching means 61, 63 atthis stage has then` no effect on the system.

.Now when the water W rises to a level so that the float 51 is floated and raised, which is accomplished when the water reaches the high water-level HW shown by the dot and.

I -dash line at vthe top 'of the tank, the arm 53 drops away. from the contacts 55 breaking the circuit 39 so that thesoleno-id 42 is de energized and the spring 43 closes thevalve 18. Closingof the valve 18 stops the Kflowing- `in ofwater. It will be clear therefore, that the water cannot exceed a higher level than that determined by the float 51 and shown as level HW.

The valve 14 in the oilinlet line 13 is now opened so that oilO; flows into the tank 10 through the inlet line 13. This oilO'oats upon the surface of the Water W and when it O continuing to flow into the With the oil -tank 10 the floatl33 continues to rise arl shortly after the lswitching means 35, 37 is opened the switching means 35, 38 is closed.

As previously discussed, the switching` means 61, 63 is closed so thatclosing of switching means 35, 38 completes the electrical circuit 40 and the solenoid 45 is energized which opens the water outlet valve 21 against the tension of the spring 46 and the water W'flows out through the outlet con-` nection 20 and valve 21 as the oil flows into the tank. The valve 21 remains'open so long as the ioat 33 is raised'suiciently to main tain the switching means 35, 38 in closed position.

`With the-oil O flowing into the tank 10 through the inlet line 13, it is important that the water W flow out through the water out let connection 2O at a rate at least as fast as the oil flows in, in order to preventA flooding of the tank. This result is readily acoomplished by having the oil inlet 13 no larger than the waterl outlet connection 20 and preferably it should besomewhat smaller in order to assure against flooding of the tank.

The water W continues to lflow out through the outlet connection20 and the oil Ol con tinues to flow into the storage tank 1() through the inlet 13 until the -water reaches the low water level LW in the tank. Aspreviously mentioned, thefloat 59'f1oats on the water W but sinks in the'oil O so that when the water reaches the low Water level LW,the float 5 9 drops, thereby raising' the arm 61 and breaking the electrical lconnection between the contaets 63 through the arm.v The solenoid 45y is deenergized land lthe spring 46 closes the valve 21. The valve 14 should then be closed or closed when the operator notes the arm 35 dropping in orderrto prevent flooding of the tank. 7

The control of theinflow of oil is also automatic to preventv flooding of the tank when the circuit is introduced into the storage system. Vith this circuit the pump is automatically stopped or instead if an automatic valve is providedas mentioned herein, when thevoil reaches high oil level H0. This automatic control operates `as follows, the oil reaching the float 33 raises the same and closes the switch contacts 35, 3 8.

As previously described this switch controls" thecircuit 40 and the valve 21 but inaddition, this switch 35, 38 controls also the cirs cuit 75. so vthat a circuit is closed from the switch 66 through the switch 35, 38 and circuit 75 to the solenoid 76 and then back pump so that the feeding in of oil is dis continued. In a gravity feed system anautomatic valve such as valve 70, 71h01' 21, 45 vcan be utilized to shutoff the inflow of oil.

The tank 10 may also'be filled in the fol- ,lowing manner. The by-pass valve 23 in the outlet by-pass connection 22 is opened so that the water flows into the tank. The4 operator watches the; level of the water until it reaches the level HW at whichtimehe closes the by-pass valve 23.Vv The downward move-l ment ofthe arm 53 offers one means of determiningl when the level HW is reached. The outlet by-pass valve 25 in the by-pass Connection 24is then opened and the valve 14 is also opened so`that the water flows out of the tank as it is being filled with oil. The movement of the arm 61 will inform the operator when the low Waterlevel LW for the water W has ybeen reached at which time the 'outlet by-pass valve 25 is closed. The level of the water should'be slight-ly above the low water level LW so that the float 59 will keep the arm 61 in engagement with the contacts '63 and thereby close the electrical circuit 40 at thispoint.- Similarlyymovement ofthe arm 35 will inform the operator Whenthe oil has reached -its high o il vlevel scribed, provides a completely automatic storage system which does not require the constant attention of anl operator. v y'For' purposes of convenience' in illustratio'n and description, the solenoid operated valves 18 and'21 with the inlet by-pass connection 22 and the inlet by-pass'va'lve 23 in thisconnection for by-passing the valvei18 as well .as the outlet by-pass connection 24y with the by-pass outlet valve' 25 in this connection for by-passing the yvalve 21 has been 'shown,but in the actualcommercial construction, the solenoid valves 18 and 21 with their by-pass valves 23 and 25 are substitutedl by` the -motor actuated valves70, -71. This electricmotor operated valve 70, 71l may be s o controlled by switching mechanism manufactured by the same, company who manu-V factures the valve itself, that the valve 70 may be opened or vclosed at' will which is the equivalent of the manually operated by-pass i valves 23 and 25 for by-passing the electricallyjoperated valves 1,8 and 21.k By this same switchi --mechanism the valves 70, 71 may be switc ed to -anl automatic connection so 'that the valve functions automatically in the' A same `manner thatfthe solenoids 42 and 45 'with the float controlled vswitches automatically operate the valves 18 and -21 in a mani l ner which willbe described.A

level is maintained substantially'fixed inY 10 irrespective of changes resulting' In the non-breathing' action of the` storage system, the lmanner in'which the liquid the t from iquid transference, temperature orl otherL causes, will; now be described. As

y previouslydescribed, the arm 61'is in e'ning the leve '33 rises with the rising level of the liquid gagement lwith thecontacts .63 so that the electrical circuit'40is closed at this oint. It'has also -been previously mentione that the arm35 is outy f'engagement witheither f f the contacts 37 or 38.' The float 51 being immersed in 'o il O sinks and closes the electrical circuit 39 atthis, oint through-the contacts 55 and arm 33.' ssuming now that .,the temperature rises so that the liquids within thestorage ofthe liquid therein, the float and closes the electrical circuit between the contacts 38 by the arm- 35 engaging` these i contacts. This completes electrical circuit-40 so that the solenoid is energized and the valve 21 is opened and the water W then flows out through the outlet connection 20 until the level of t eliquid drops. "I he float 33 falls with the dropping liquid'- level and breaks the electrical circuit 40 at the contacts 38. `This opens the electrical circuit 40 and the the loss of noid 42 an 'through the inlet connection 17 so that the tank 10 expand, thereby raissolenoid'45i's' deen'ergized so that the spring '46 closes the valve 21. Itis clear that if the liquid continues to expand, the above described action repeats itself.

If now the `li uids in the storage tank 10 contract, as usua l occurs by cooling of the liquids in the tanr with the cooling of the air surrounding the tank during the ni ht time, the upper level of the liquid wit in thetank is lowered and the float 33 drops with the liquid level so that the switchbladel or-arm 35 engages the contacts37 and closes the electrical circuit 39. As previously mentioned, the-circuit ^39 is already closed throu h the contacts and arm 53. Closing o the electrical circuit 39 through the contacts 37' energizes the solenoid 42 which opens thevalve.18 and water flows into the storage tank 10 through lthe water inlet cony nection 17. The flowing in of the water raises th'elevel ofthe liquid in the tank until -the float 33 rises sutliciently to break the engagementof the arm 35 with thev contacts '37 which opens the electrical circuit 39 and the solenoid 42 is deenergized s0 that the spring 43 closes the valve 18. It is clear that if the liquids within the storagev tank 10 continue torcontracthe operation just described wlll repeat itself as often as may be necessary to maintain the /liquid at a substantially constant level within the tank, namely, at

the high. oil .level HO.- Maintaining the level ofA the liquid within the storage tank 10 at a substantially constant level, practically eliminates breathing of the tank and evaporated stored liquid from the .l The storage .system also functions as a safet 'and automatic system in withdrawing the, llfrorn-the tank." In order to withdraw the stored liquid or oil, the valve 12 is Aopened and the oil flows out through the oil outlet 11. The oil flowing out of the tank lowers the 'liquidlevel and the vfloat 33 falls with the falling liquid level. The dropping float 33'gbrings the arm 35 into engagement with thecontacts 37 which closes the electrical circuit 39 and energizes the solenoid l42 as previously described. vv'The valve 18 is opened u on the energization of the sole- -water.W Hows into the tank level ofthe oil will not fall below the outlet connection 11 at the top of the tank. If now thevalve 12is closed, the water W will continue to'flow into the tank untilthe fioat 33 is raised and breaks the electrical circuit- -bel withdrawn therefrom at any time and so that its' level willnot fall below the oil outlet 11 at the top ofthe tank.

which level the float 51 rises since this float sinks in the oil O but floats upon the water W. rlhe raising of the float 51 breaks theelectrical circuit 39 at the contacts 55 which deenergizes the solenoid 42 and the valve 18 in the water inlet connection closes under the influence of the spring 43. The level of the water W is therefore prevented from going higher than or exceeding the high water level HW and, consequently, it will not be possible to draw off water through the oil outlet ll.

When the tank 10 is filled with oil and the water outlet valve 21 is automatically opened so that the level of the Water reaches the low water level LW, the float 59 which floats on the water but sinks in the oil or stored liquid, falls with the dropping level of the displacement liquid or water and breaks or opens the electrical circuit 40 at the contacts 63. With the-electrical circuit40 open, the solenoid /15 is deenergized and the spring 46 closes the valve 21 so that further voutflow of water through the outlet connection 2O ceases. llt Kwill be seen, therefore, that the level of the water is automatically prevented from receding below a predetermined low water level L-VV and, consequently, it will not be possible for the oil to be wasted out through the outlet connection 20 for the Water.

The invention has then, automatic control for maintaining the level of the liquid in the tank at a substantially constant predetermined level irrespective of expansion and contraction of the liquids in the tank due to temperature changes or to changing levels 1oecause of liquid transference to or from the tank or because of other causes. Again the level of the water is automatically prevented from exceeding a predetermined level and automatically prevented from receding below a predetermined level during the hydraulic filling or discharging of the oil or water from the tank. Then too the feeding in of oil into the tank is automatically controlled so that flooding of thetank cannot occur.

I claim:

1. A liquid storage system comprising a tank, at least one stored-liquid connection therewith, a displacement-liquid inlet connection with the tank, a displacement-liquid outlet connection at the bottom of the tank,

a valve in the inlet connection, a valve inthe outlet connection, an electrical actuating means operatively connected to each valve, a float positioned adjacent the top of the tank and which floats on the upper surface of the stored liquid and is controlled by the movement of said surface, and electrical switch means interconnected between the float and the electrical actuating means for opening and closing said valves to regulate the inflow and outow of displacement liquid to maintainv the upper surfaceA of the stored liquid at a substantially .predetermined level in the tank. i

2. A liquid storage system comprising a tank, at least one stored-liquid connection therewith, a displacement-liquid inlet. connection with the tank, a displacement-liquid outlet connection into the tank proximate the bottom thereof, a' valve in the inlet connection, a valve in the outlet connection, electrical actuating means for the valves, a float resting on theupper surface of the stored liquid and controlled by up and down movement of the surface, an arm connected to the float and movable therewith, switch means closed by the arm when the float rises and" connected with the electrical actuating means for the valve in the outlet connection for opening said valve to permit displacement liquid to How out of the tank, and switch means closed by the arm when the float falls and connected with the electrical actuating means for the valve in the inlet connection for closin said valve to permit displacement liquid to ow into the tank.

.3. A liquid storage tank system and means to maintain the upper surface of the stored liquid at a substantially constant level and the displacement liquidwithin at least one limiting level comprising a tank, a displace ment-liquid inlet and a displacement-liquid outlet connection with the tank, a valve in; the inlet connection to admit displacement liquid in event the stored-liquid level has a tendency to lower in the tank, a valve in the outlet to drain olf displacement liquid in event the stored-liquid level tends to rise in the tank, a system of Heat-control means including a float which oats on the stored liquid and positioned at the stored-liquid level, and a float which sinks in the stored liquid but floats on displacement liquid and positioned at one of the limiting levels for the displacement liquid, and means interconnected between the system of floats and the valves for opening and closing said valves to maintain the stored-liquid at a substantially constant level excepting. when the displacement liquid is at one of its limiting levels.

f1. A liquid storage tank system and means to maintain the upper surface of the stored liquid at a substantially constant level and the displacement liquid within 'at least one limiting level comprising a tank, a displacement-liquid inlet and a displacement-liquid outlet connection with the tank, a valve in vuid and positioned at the stored-liquid level,

and a float which sinks in the stored liquid but floats on the displacement liquid and positioned at one of'the @limitinglevels for the displacement liquid, and electrically operated means. interconnectedibetween the system of floats and the valves foropening and closingsaid *valves to maintain a .substan- 'tially constant stored-.liquid level aforesaid excepting when the'displacement .liquidis at one of its limiting levels.

5. A liquid storage systemcomprising a tank, fill and delivery ipes connected with the tank for filling and di'awing off the liquid to be stored, displacement-liquid inlet and outlet pipes connected withthe tank through which liquid `flows to and from the' tank to maintain the upper surface of the stored .liquid at substantially a constant level, motoractuated valve means in the inlet and outlet pipes, an electric circuit connected'with the motorfactuated valve means, switch means included in the electric circuit, and float means in .the tank operatively connected with the swltch means by which a change in elevation of the surface of the vstored liquidl acts through the float means -to operate the motoraotuated valve .means either to admit or drain ofi' the displacement liquid to maintain the constant level.

6. A liquid storage tank system comprising a tank, at least one stored liquid connection therewith, a displacement liquid inlet and a dlsplacement liquid outlet connection with the. tank, avalve in the 'inlet connection, a valve in the outlet connection, a first'float positioned adjacent the top of the tank which floats on .the upper surface ofthe stoned liquid and is controlled by the up and down movement thereof, :a second fioat whichi'fioats inthe displacement liquid but sinksin the' stored liquid and is controlled by the up and down movement of the liquids in the tank,- sald second float being adjacent the top of the tank and positioned vbelow the firstfloat,`

and means interconnected between the floats and the valves for opening and closing said valves to maintain the upper surface of the stored liquid-at a substantially predetermined level and to prevent the upper surface of the d1sp1acement liquid from exceeding a predetermined level. 4

7. A liquid storage tank system comprising a tank, at least one displacement-liquid inlet connectigny therewith, a displacement-liquid outlet connection with the tank, a valve in the inlet connection, a valve in the outlet connection, afirst flmt adjacent the top of the .tank

which iioats'om the surface of the stored liq uid and being controlled by the changein level of said surface, a second float whlch floats on ythe displacement liquid but sinks in the stored liquid and being controlled by the change of liquid levelin the tank, said second fioat being positioned adjacent the top of the tank and below the first float, means interconnected between the first float and each valve for opening and closing said valves to maintain the stored liquid at a substantially predetermined level,- and means interconnected with the second-float and the inlet connection valve to prevent the displacementliquid from exceeding a redetermined level.

8.. A liquid storage tan system comprising atank, at least one stored liquid connection therewith, a' displacement-liquid inlet and a displacement-liquid outlet connection with the tank, a valve in the inlet connection, a valve in .the outlet connection, a first float- Which floats on the stored liquid and is controlledby the up-and down movement of the rnected with the electrical actuating means of both valves for opening and closing said valves to maintain the upper surface of the stored liquid at a substantially predetermined level, and switch means controlled by the second float and connected with the electrical actua-ting means for the valve in the inlet connection and in ries with the switch.

means for the first float to -prevent the displacement liquid from exceeding a predeterminedlevel. i Y

9. A liquid storage tank system comprising a tank, atleast one stored-liquid connection therewith, a displacement-liquid inlet connection anda displaoementvliquid outlet connection with the tank, a valve in the inlet connection, 4a valve in the outlet connection, a first float` adjacent the top of the tank which floats onthe stored liquid upper surface and is controlled bv change in level thereof. another v and a displacement-liquid outlet connection with the bottom of the tank, a valve in the inlet connection, a valve in the outlet connec-v 4other float being positioned adjacent the bot- Qnamed float being positioned proximate the' tank, at least one stored-liqllid connection tom'of'the tank, means interconnected between the first float and both valves for opening `and-closing said valves to maintain the stored liquid upper surface at a substantially predetermined level, and means interconnected between the float at the bottomof the tank and the valve in the outlet connec- Ition to prevent the displacement liquid from receding below a predetermined level.

11. A liquid storage tank 4system comprising atank, at least one stored-liquid connection therewith, a displacement-liquid inlet and a displacement-li uid outlet connection made at the bottom o the tank, a valve in the inlet connection, a valve in the outlet connection, a first'float adjacent the top of the tank which fioats on the stored liquid surface and is controlled by change-in level thereof, another float which fioats on the displacement liquid but sinks in the stored liquid, the last displacement-liquid connection at the bottom of the tank, electrical actuating means to operate both valves, switch means controlled by the first float and connected with the electrical actuating means of both valves for opening and closing said valves to maintain the stored liquid upper surface at a substantially predetermined level, and switch means controlled by the other float and connected with the electrical actuating means for the valve in the displacement-liquid outlet connection and in series with the switch for the rst float to prevent the displacement liquid from receding below a predetermined level.

12.' Arliquid storage system comprising a therewith, a displacement-li uid inlet connection and a displacement liquid outlet connection at the bottom of the tank, a valve in the inlet connection, a valve in the outlet connection, a rst float proximate the top of the tank and which fioats on the stored liquid, a pair of floats which sink in the stored liquid but float on the displacement liquid, one of ".said pair of floats being positioned adjacent .the top of the tank but below the iirst fioat and the other loat being positioned adjacent the bottom of the tank, and means interconnected between the floats and the valves for opening and closing said valves to maintain the stored liquid upper surfaceat a substantially predetermined level and to prevent the displacement liquid from exceeding a predetermined high level and 'from receding below a predetermined low level.

13. A 'liquid storage system comprising a tank, at least one stored-liquid connectlon therewith, a displacement-liquid inlet connection and outlet connection with the bottom of the tank, arvalve in the inlet connection, a valve inthe outlet connection, a first fil-oat at the top of the tank which fioats on the stored liquid, a pair of tloats'which sink in the stored liquid but fioat on the displacement liquid, one of said pair of fioats being positioned proximate the top of the tank but below the first oat and the other float being positioned adjacent the bottom of the tank,

means interconnected between the first fioat and both valves for opening and closing said valves to maintain the' stored liquid upper surface at a substantially predetermined level, and means interconnected between the pair of fioats, and the first fioat and both valves to prevent the displacement liquid upper surface from exceeding a predetermined high level and from receding below a predetermined low level.

14. A liquid storage system comprising a tank, at least one stored-liquid connectlon proximate the top of the tank, a displacement-liquid inlet connection and outlet connection at the bottom of the tank, a valve in the inlet connection, aA valve in the outlet connection, a first i-oa-t vwhich floats on the stored liquid, a pair of floats which sink in the stored liquid but fioat on the displacement liquid, one of said pair of floats being a high level oat and positioned below the first float, the other 'loat 'being a low level fioat and positioned adjacent the bottom of the tank, means interconnected between the first float and the valves for opening and closing`said valves to maintain the stored-liquid upper surface at a substantially predetermined level, means interconnected between the high level oat and the first float and the inlet valve to prevent the displacement liquid from exceeding a predetermined high level, and means interconnected between the low level float and the first oat and the outlet valve to prevent the displacement liquid upper surface from receding below a predetermined low level.

15. A liquid storage system comprising a tank, stored-liquid connection means therewith to fill the tank and draw ofi' the stored liquid, a displacement-liquid inlet connection at the bottom of the tank, a displacement-liquid outlet connection at the bottom of the tank, a valve in the inlet connection, a Valve in the outlet connection, electrical actuating means for the valves, a first fioat which floats on the stored liquid, a pair of fioats which sink in the stored liquid but float on the displacement liquid, one of said pair of floats being positioned below the first` float and the other float being positioned adjacent the bottom of the tank, switch means interconnected between the floats and the electrical actuating means for opening and closing the valves to maintain the stored liquid upper surfaceat a substantially redetermined level and to revent the dis 'acement liquid from exceeding 5 a predetermined high level and receding below a predetermined low level.

16. A storage system for oil comprising a storage tank above'the ground, a pi e connected proximate the to lof the tan to fill l0 and deliver oil to and rom the top of the tank, conduit means proximate the bottom of the tank to fill and deliver water to and from the bottom of the tank under the oil, valve means in the conduit means by which the flow of water to' and from the tank is controlled; motor means o eratively connected with the valve means; t ree floats two of which are proximate the tos of the tank, one of the two floats adapte to norin'all float on the 90 surface of the oil but the ot er fioat normally sinks in oil; the third float being located at the bottom of the tank and normally floatsY in water, and electrical circuit s and switch means interconnected between the u three fioats and valve means to maintain the upper surface of the oil lagainst the top of the tank and to prevent the up r surface of the water from reaching either top or ,bottom of the tank. 3 17. A liquid storage system comprising a tank, an oil connection therewith to fill the tank and draw of the oil, a water inlet connection'at the bottom of the tank, a water outlet'connection at the bottom of the tank, a valve in the inlet connection, a valve in the outlet connection, electrical actuating means for the valves, a first float which fioats on the oil positioned at the top of the tank, a second float which sinks in stored oil and 4 floats on water positioned vat the top of the tank but below the first float, a third float which sinks in oil and floats on water positioned at the bottom of the tank, a pair of v switches controlled by the first float, one of said pair of switches being closed u on upward movement of the first float wi a rising liquid surface in the tank and connected to the actuating means for the valve in the v outlet connection, the other switch being 5 closed upon downward movement of the first float with a lowering liquid surface in the tank and connected to the actuating means for the valve in the inlet connection, a switch controlled by the second float and connected '55 in series with the lowering li uid surface switch of the fiist float, a yswitc controlled by the third float and connected in series with the switch rising liquid surface switch of the first float, means connecting the lowering.l liquid surface switch with the actuating means for the inlet valve, and' means connecting the rising liquid surface switch with the actuating means for the outlet valve.

18. A liquid storage system comprising a,

tank, an oil connection therewith to fill the tank and draw off the oil, a water inlet connection at the bottom of the tank, a water outlet connection at the bottom of the tank a valve in the inlet connection, a valve in t e outlet connection, electrical actuatin means for the valves, a float box projectin a ve the top of the tank, a first float which oats on the stored liquid positioned within the fioat box a second float which sinks in stored oil an floats on water positioned ,at the top of the tank 'but below the first float,"a third float which sinks in oil and floats on water ositioned at the bottom of the tank, a pair of switches controlled by the first fioat, on'e of said pair of switches being closed u on upward movement of the first float wit a rising liquid surface in the tank and connected to the actuating means for the valve in the outlet connection, the other switch being closed upon downward movement of the first float with a lowering liquid surface in the tank and connected to the actuating means for the valve in the inlet connection, a switch `controlled by the second float and connected in sexies with the lowering li uid surface switch of the first float, a switc controlled by. the third float and connected in series with the switch rising liquid surface switch of the first float, means connecting the lowering liquid surface switch with the actuating means for the inlet valve, and means connecting the rising liquid surface switch with the actuating means for the outlet valve..

19. A liquid storage system comprising a tank, an oil connection therewith to fill the tank and draw off the oil, a water inlet connection at the-bottom of the tank, a water outlet connection at the bottom of the tank, a valve in the inlet connection, a valve in .the outlet connection, electrical motor actuating means for the valves, a first float which floats on the oil positioned at the top of the tank, a

second float which sinks in stored oil and fioats on water positioned at the top of the tank but below the oil outlet, a third float which sinks in oil fand floats on water positioned at the bottom of the tank, a pair of switches controlled by the first float, one of said pair of switches being closed u on u pward movement of the firstvfloat wit a rising liquid surface in the tank and connected to the actuating means for the valve in the outlet connection, the other switch being closed upon downward movement of the first fioat with a lowering liquid surface in the tank and connected to the actuating means for the valve in the inlet connection, a switch controlled by the second float and connected in series with the lowering li uid surface switch of the first float, a switc controlled by the third float and connected in series with the rising liquid surface switch of the first float, means connecting the lowering liquid -surface switch with the motor actuating: means for the inlet valve, means connecting motor actuating means for the outlet valve,

n and m3111131 IllelIlS t COIltlOl lille lllOllOl 3C- tuated means to open or close each valve i11- dependently of the float controlled switches. 20. A liquidr storage system comprising 'a tank, at least one stored-liquid connection therewith, a displacement-liquid inlet connection with the tank, a displacement-liquid outlet connection at the bottom of the tank, a valve in the inlet connection, a valve in the` outlet connection, an electrical actuating means operatively connected to each valve, a float positioned adjacent the top of the tank and which floats on the upper surface of the stored liquid and is controlled by the movement of said surface, electr' cal switch means interconnected between the float and the electrical actuating means for opening and closing said valves to regulate the infiow and outflow of displacement liquid to maintain the upper surface of the stored liqud at a substantially predetermined level in the tank, and means to automatically stop the feeding in of stored liquid into the tank when the high stored liquid level is reached.

21. A liquid storage system comprising a tank, at least one stored-liquidl connection therewith, a displacement-liquid inlet conne( tion with the tank, a displacement-liquid outlet connection at the bottom of the tank, a valve in the inlet connection, a valve in the outlet. connection, an electrical actuating means operatively connected to each valve, a float positioned adjacent the top of the tank and which fioats on the upper surface of the stored liquid and is controlled by the movement of said surface, electrical switch means interconnected between the float and the electrical actuating means for opening and closing said valve to regulate the inflow and outflow of displacement liquid to maintain the upper surface of the stored liquid at a sub-y stantially predetermined level Vin the tank, and means controlled by the float to automatically stop the feeding in of stored liquid into the tank when the rising stored liquid raises the iioat. I

22. A liquid storage system rcomprising a tank, at least one stored-liquid connection therewith, a displacement-liquid inlet connection with the tank, a' displacement-liquid outlet connection at the bottom 'of the tank, a' valve in the inlet connection, a valve in the outlet connection, an electrical actuating imeans operatively connected to each valve, a floatpositioned adjacent the top of the tank and which floats on the upper surface of the stored liquid and is controlled by the movement of-said surface, electrical switch means interconnected between the float and the electrical actuating means for opening and closstantially predetermined level in the tank, and electrical means controlled by the/ switch means to automatically stop the'fee'ding in of oil into the tank when the oil level raises theiioat.

23. A liquid storage tank s stem comprising a tank, at least one store liquid connection therewith', a displacement-liquid inlet and a displacement-liquid outlet connection with the tank, a valve in the inlet connection, a valve in the outlet connection, a first float .which floats on the stored liquid and is controlled by the-.up and down movement of the upper surface of the liquid in the tank, a second float which floats on the displacement liquid but sinks in the stored liquid and is controlled by the up and down movement of the liquid in the tank, said second float being positioned below the first float, electrical actuating means Ato operate both valves, switch means controlled by the first float and connected with the electrical actuating means of both valves for opening and closing said valves to maintain the upper surface of the stored liquid at a substantially predetermined level, switch means controlled by the second ioat and connected with the electrical actuating means for the valve in the inlet connection and in series with the switch means for the first float to prevent the displacement liquid from eX- ceeding a predetermined level, and means controlled by the switch means of the first float to automatically shut off the inflow of stored liquid when the liquid raises the float.

24. A liquid storage tank system comprising a tank,.at least one stored-liquid 2onnection therewith, a displacement-liquid inlet and a displacement-liquid outlet connection made at the bottom of the tank, a valve in the inlet connection, a valve in the outlet connection, a first float adjacent the top of the tank which floats on the stored liqv uid surface and is controlled by change in level thereof, another iioatwhich floats on the displacement liquid but sinks in the stored liquid, the last named float being positioned proximate `the displacement-liquid connection at the bottom of the tank,.elee trical actuating means to operate both valves, switch means controlled by the first float and connected with the electrical actuating means of both valves for opening and closing said valves to"maintain the stored liquid upper surface at a substantially predetermined level, switch means controlled by the other Heat and co nected with the electrical actuating mea s for the valve in the displacement-liquid outlet connection and in series with the switch for the first float to prevent the displacement liquid from receding below a predetermined level, and means controlled by the switch means of the first float to automatically shut oft' the inflow of stored liquid when the liquid raises the float.

"controlled by A liquid storage system comprising a tank, an oil connection therewith to fill the tank and draw off the oil, a water inlet connection at the bottom of the tank, a water outlet connection at the bottom of the tank, a valve in the inlet connection, a valve in the loutlet connection, electrical actuating mearfs for the valves, a first float which floats on the oil positioned at the top of the tank,

a second float which sinks in stored oil and floats on water positioned at the top of the tank but .below the first float, a third float which sinks in oil and floats on water ositioned at the bottom of jthe tank, ay palr of switches controlled by the first float, one of said pair of switches being closed u n upward movement of the first fl'oat wit a rising liquidl surface in thetank and connected to the actuating means for the valve in the outlet connection, the other switch being closed upon downward movement of the first l float with a lowering liquid surface -in the tank and connected to the actuating means for the valvein the inlet connection, a switch the second float and connected 4 in series w1th the lowering li uid surface switch of the first float, a switc controlled by the third float and connected in-series with `the switch rising liquid surface switch of the first float, means connecting the lowering liquid surface switch with the actuating means for the inlet valve, means connecting the rising liquid surface switchy with the actuating means for the outlet valve, and

means controlled by the rising liquid surface switch of the first float to automatically shut off the inflow of stored liquid when the liquid raises the float.

In testimony whereof I ailix my signature.

' WILLIAM J. PETER. 

